Optimization of determination of CO2 gas hydrates surface tension in the presence of non-ionic surfactants and TBAC

The gas hydrates formation, in spite of its disadvantages, has some advantages such as separating, transferring and storing gas.  Therefore, determining the appropriate promoters for the gas hydrates’ formation is as important as selecting an appropriate inhibitor.  One of the effective promoters is TetraNButyl ammonium chloride (TBAC). Due to TBAC’snondestructive environmental effects and its extraordinary effect on the thermodynamics of gas hydrates, this salt is one of the most widely used promoters.  TBAC  was  discussed  in  the  context  of  hydrate  structure  formation  and Alkyl  Poly  Glucoside  (APG)  as  a  nonionic  surfactant  due  to  biodegradability, emulsifiers,  and  reasonable  prices.  In this study, the surface tension between CO2hydrates   was   evaluated   at   constant   temperatures   and   pressures   with   different concentrations.  For this purpose, the classical nucleation theory has been used.  The experimental data show that at constant temperature, the induction time was reduced by increasing the TBAC concentration and adding APG. Also, the surface tension value reduced  significantly  by  adding  APG,  led  to  an  upward  trend  with  increasing temperature. Finally, the surface tension values obtained from the developed method were compared by presented correlations. The results of the developed model are in satisfactory agreement with literature data.